Persons with abductor spasmodic dysphonia (ABSD) have difficulties with phonation onset after voiceless consonants resulting in breathy breaks. Previously, ABSD was thought to involve heightened activity of the laryngeal abductor muscle, the posterior cricoarytenoid. Botulinum toxin injection of the posterior cricoarytenoid muscle in this disorder, however, only provides a partial benefit in about 50% of persons with ABSD. An electromyographic study of the laryngeal muscles in ABSD found asymmetries in the adductor muscle (the thyroarytenoid muscle) in ABSD. Thyroarytenoid (TA) activation levels differed between the two sides in persons with ABSD. An electromyographic study of the laryngeal muscles in ABSD found asymmetries in the adductor muscle (the thyroarytenoid muscle) in ABSD. Thyroarytenoid (TA) activation levels differed between the two sides in persons with ABSD in comparison with controls; the right TA showed greater activity than the left. This suggested that ABSD might involve increased tone on one side of the larynx, and that treatment should address any such asymmetry in muscle tone. We hypothesize that if TA muscle activity was greater on one side in ABSD, then